Tom Gonzales and his son, Thomas J. Gonzales II, made a fortune from their company, Silicon Valley online-commerce pioneer Commerce One, before young Thomas' death from cancer, at 35, back in 2001.

The family buried him as befits a dot.com pioneer -- in a $3.2 million (plot included) white stone family mausoleum at Oakmont Memorial Park in Lafayette, Calif.

After Commerce One's bankruptcy and sale in 2004, the father relaunched himself as a real estate developer, built a $50 million family compound in Lake Tahoe (400-space garage, RV elevator), and sued a Silicon Valley charitable foundation over control of Thomas' estate, valued at $91 million in a 2007 court case.

But Thomas's mortal remains haven't been allowed to rest in peace.

In January thieves cut, pried and smashed their way past the mausoleum's chained steel doors and glass interior and stole the gold-colored metal urn containing the dead man's ashes.

Despite a $10,000 reward offer, the family says it has found no trace of urn or ashes.

So they want a refund. On Tuesday, Tom Gonzales sued Oakmont Memorial Park's owner, a unit of Levittown, Pa.-based StoneMor Partners LP, in the Contra Costa County court, alleging "negligent infilction of mental distress" and negligence in general. There'd been an attempted break-in a few nights before, which Gonzales says StoneMor's managers failed to report.

Tom wants his $3.2 million back, plus money to build another mausoleum for surviving family members: Without Thomas' remains "the mausoleum is a useless structure, the sight of which causes Tom Gonzalez great pain and suffering."

StoneMor officials declined to comment. The company bought the cemetery as part of an acquisition after Gonzales' burial but before the theft.